1. Field of the Invention
The present invention relates to a test apparatus and a test method for testing an electronic device in which a field effect transistor is provided, an electronic device in which a field effect transistor operating in response to a given test pattern is provided and a method for manufacturing the device. More particularly, the present invention relates to a test apparatus and a test method for reducing influence of the change of a leak current in the field effect transistor during the test.
2. Description of the Related Art
Conventionally, as a method for testing an electronic device such as semiconductor circuit, a method for measuring a power supply current supplied for the electronic device and detecting an abnormal value of the power supply current has been known. For example, a variety of test patterns are applied to the electronic device, the power supply current is detected in various operating states and the acceptability of the electronic device is decided on the basis of whether the power supply current is within a predetermined range or not.
Since related patent documents have not been found up to the present, the description regarding the documents is omitted.
However, the leak current in the electronic device has been increased due to miniaturization of the electronic device or increase of the number of CMOS included in the electronic device. The leak current changes according to differences among the electronic devices or the change of the temperature. Particularly, for the CMOS, the so-called sub-threshold leak current has high temperature dependence and it is difficult to stabilize the sub-threshold leak current. For this reason, the power supply current supplied to the electronic device changes according to the change of the leak current and the conventional power supply current test has a problem of deciding that an electronic device which has no defect is defective.
Further, regarding the above problem, the method for providing the electronic device with a temperature sensor and a heater and controlling the temperature of the electronic device to be constant has been known. However, this kind of control cannot perform a precise control and make the change of the leak current sufficiently small.